Multiple bit attachment for drilling tool



April 26, 1955 L. F. BLATT MULTIPLE BIT ATTACHMENT FOR DRILLING Toor.

Filed March 30, 1955 2 Sheets-Sheet l INVENTOR. LELN D F. BLATTJATTORNEY .April 26, 1955 l.. F. BLATT MULTIPLE BIT ATTAcmmENT FORDRILLING Toor.

Filed March 5o, 195s 2 Sheets-Sheet 2 FIGA.

FIG. 3.

FIG.7.

INVENTOR.

LELAND F.BLATT mmf- United States Patent MULTIPLE BIT ATTACI-MENT FORDRILLING TO L Leland F. Blatt, Detroit, Mich.

Application March 30, 1953, Serial No. 345,635

6 Claims. (Cl. 77-55) This invention relates to multiple bit drillingdevices and particularly multiple bit attachments for drilling tools.Said invention may be considered an improvement on the adjustable drillguide and pilot disclosed by my Patent 2,461,716 of February l5, 1949.

An object of the invention is to establish a dr1ve connection from astem to a plurality of bits, to dispose such connection within a housingjournaling the stem and bits, and to guide such housing in travel to andfrom the work, the guide means having a portion for seating on the work,and said housing constraining the stern and bits to slide in unison.

Another object is to employ gears to establish the described driveconnection.

Another object is to adjustably regulate the sliding advance of saidstem and bits relative to said guide means, thus suiting the attachmentto different thicknesses of work.

Another object is to employ a slide guide for said housing equipped withan extension Slidable in a support adapted for rigid attachment to anon-rotating portion of a drilling tool, said support carrying anelement engageable with the slide guide to limit advance of the stem andbits, and such element being adjustable to regulate such advance.

Another object is to equip said slide guide with a dowel for receptionin an opening of the work, and to thus predeterminedly locate the bitswith relation to such opening.

Another object is to provide a spring effective to retract the drivingstem and bits to an initial drilling position with relation to saidslide guide.

These and varous other objects are attained by the constructionhereinafter described and illustrated in the accompanying drawings,wherein:

Fig. 1 is a side elevational view of my improved attachment.

Fig. 2 is an axial sectlonal view of the same as applied to a drillingtool, omitting the cover of the slideguide.

Fig. 3 is a cross sectional view taken on the line 3 3 of Fig. 2 andparticularly showing a provision for clamping my attachment to adrilling tool.

Fig. 4 is a front end view of the slide-guide.

Fig. 5 is a perspective view of a key used to interlock certain parts ofthe attachment.

Fig. 6 is a cross sectional view of the slide-guide and of a gearhousing within such guide, taken on the line 6 6 of Fig. 2.

Fig. 7 is a cross section on line 7 7 of Fig. 2 showing how the bits areguided at the front end of the slide-guide.

Fig. 8 is a perspective View of the gear housing.

In these views, the reference character 1 designates the frame of adrilling tool, 2 a shaft journaled in said frame and usually driven byan electric motor (not shown), and 3 a chuck carried by the shaft 2 andgripping a bit in ordinary use of said drilling tool. My attachmentcomprises a stem 4 for insertion in said chuck, and a guide supportincluding a split collar 5 adapted to be clamped on the frame 1 by ascrew 6, an arm 7 integrally projecting from said collar alongside thechuck, a head 8 on the front end of the arm projecting across the frontend of the chuck, and an elongated tubular member 9 rigidly forwardlyprojecting from the head 8 and coaxial with the stem 4. The head 8 hasan opening 10 accommodating the stem and affording it clearance.Slidably fitted in the member 9 is a tubular extension 11 from 2,706,918Patented Apr. 26, 1955 ICC the rear end of a slide guide 12, saidmemberand extension jointly housing a coiled spring 13 tending toretract the drilling tool 1, 2, 3 and the support 5, 7, 8 9 to a desiredinitial drilling postion. A key 14 set into an elongated recessexteriorly formed in the member 9 has an inturned forward end 14aprojecting into a slot 15 longitudinally extending in the extension 11,such key thus restraining the slide guide 12 from rotation and servingalso to limit forward actuation of the slide guide by the spring 13.

Slidable forward and back in the guide 12 is a rectangular housingcomprising front and rear parts 16 and 17 rigidly interconnected byscrews 18. Stub shafts 19 carrying pinions 20 are journaled in saidhousing in parallelism with and at opposite sides of the stem 4, and aremeshed with and driven by a pinion 21 fixed on said stem. Screwed intothe two stub shafts are a pair of forwardly projecting bits 22 having asliding tit in a workengaging projection 23 formed on the front end ofthe guide. The length of such bits is such that their cutting ends arein close proximity to the work-engaging face of the projection 23, whenthe housing 16, 17 is fully retracted, as in Fig. 2. In event the work23a is to be drilled at opposite sides of an opening therein, theprojection 23 may be equipped centrally thereof with a dowel pin 24 tobe slip-fitted in such opening. Between the front end of the stem 4 anda screw 25 inserted in the housing member 16, there is interposed a ball26 minimizing friction as a forward thrust is transmitted from the stemto the housing. Between screws 27 inserted in the housing member 17 andthe two stub shafts there are inserted balls 28 minimizing friction asthrust is transmitted to said shafts from the housing. The slide guidepreferably has a removable cover plate 29, said guide having one of itsfaces grooved to accommodate such plate and opposite edges of the groovebeing undercut to retain the plate in place. A screw 30 normally holdsthe plate in its closure position by securing a lug 31 on the plate tothe front end of the guide.

A nut 32 is threaded on the member 9 for a forward and back adjustmentregulating the spaced relation of such nut to the guide 12 and a locknut33 is adapted to secure such nut in any desired adjustment. Thus whensaid guide is seated against a piece of work, the nut 32 limits advanceof the stem 4 and of the bits moving in unison with such stern, so thatthe cutting stroke will not materially exceed the thickness of the work.This will safeguard the bits from damage through encountering any memberdisposed rearwardly of the work, and in some instances will avoid amutilation of such a member. It will be noted that the projection 23 iscut away at opposite sides thereof as indicated at 34, a short distancerearward of the work-engaging face of said projection. The openings 34partially expose the bits 22 and allow a discharge of chips. Afordingthe bits a slip t in the forward end portion of the guide 12 and in theprojection 23, avoids undue lateral flexure of the bits and consequentbreakage or deformation of drilled holes.

While the attachment illustrated is equipped with two bits, it isevident that a greater number of bits could be employed and driven bythe described mechanism.

What I claim is:

1.. A multiple bit attachment for a drilling tool compr1s1ng a rotatableand reciprocable driving stern and a plurality of bits parallel to suchstem, a drive connection to the bits from the stem, a housing for saidconnection reclprocable in unison with the stern, a guide having a frontand a rear end and formed between such ends with a chamber proportionedto receive the housing and afford its reciprocation, the housing havinga sliding t within such chamber and said bits being reciprocable inunison with the housing to effect their cutting stroke, and means on thefront end of the guide for seating the guide on a workpiece, said stemprojecting from the rear end of the guide to receive a drive.

2, In a multiple bit attachment for a drilling tool as set forth inclaim l, a dowel pin forwardly projecting from said guide and having apredetermined lateral spacing from the bits for entering a workpiece.

3. In a multiple bit attachment for a drilling tool as set forth inclaim 1, a ball at the axis of the stem transmitting forward thrust tothe housing, and a ball at the axis of each driven gear transmittingforward thrust from the housing to such gear.

4. In a multiple bit attachment for a drilling tool, the combinationwith a drilling tool including a driven shaft, a nonrotative portion anda chuck on said shaft, of an attachment comprising a driving stemgripped by said chuck, a plurality of bits parallel to the stem, a driveconnection to the bits from the stem, a housing for said connectionreciprocable by such connection in unison with the stem, a guide formedwith a chamber proportioned to receive the housing and afford itsreciprocation, the housing having a sliding fit within such chamber,said guide having a front and a rear end, and said bits beingreciprocable in unison with the housing to eiect their cutting stroke, atubular extension from the rear end of said guide, a support for saidattachment having a rear portion fixed on said nonrotative portion ofthe tool and having a tubular front portion in which said tubularextension is reciprocable, a spring reacting between the support andsaid extension to urge the guide forwardly, a stop element carried bysaid support and adjustable to and from the guide and engageable by theguide to selectively limit the effective stroke of the bits, and aconnection between said extension and support restraining the guide fromrotation relative to the support.

5. A multiple bit attachment for a drilling tool comprising a rotatableand reciprocable driving stem for engaging the chuck of such tool, aplurality of bits parallel to said stem, a drive connection to the bitsfrom the stern, a housing for such connection reciprocable in unisonwith the stem, a guide formed with a chamber proportioned to receive thehousing and afford its reciprocation, the housing having a sliding fitwithin such chamber, said guide having a front and a rear end and saidbits being reciprocable in unison with the housing to etfect theircutting stroke, a tubular extension from the rear end of the guidesubstantially coaxial with said stem, a support attachable to anonrotating portion of the drilling tool, such support having a tubularfront portion in telescoping engagement with said tubular extension,means restraining said extension from rotation relative to said tubularfront portion, a spring coiled about said stern and compressed betweensaid support and guide to urge the guide forwardly, and means on thefront end of the guide for seating on a workpiece.

6. .A multiple bit attachment for a drilling tool as set forth in claim5, the last-mentioned means being a projection from the forward end ofthe guide and having guiding engagement with the several bits.

References Cited in the file of this patent UNITED STATES PATENTS1,884,752 Krueger Oct. 25, 1902 2,302,853 Gordon Nov. 24, 1942 2,401,490Little June 4, 1946 2,461,716 Blatt Feb. 15, 1949

